Interface friction characteristics of precast pile with core-filled composite solidified soil

Abstract:

To investigate the influence of core-pile interface friction characteristics on the bearing capacity of filled-core composite solidified soil precast piles, this study simulated the core-pile-precast-pile interfacial contact using annular shear specimens and systematically examined the frictional behavior at their interface. The experimental results demonstrated that: The ultimate interfacial frictional resistance increases with core pile diameter enlargement; The bonding coefficient between core pile and precast pile shows a positive correlation with the compressive strength of core-filling materials, with recommended values ranging from 0.02 to 0.10; An initial frictional resistance exists at the interface, and the shear-induced friction evolution exhibits three distinct phases-elastic deformation phase, brittle failure phase, and bond-slip phase, presenting a quasi-brittle failure mode. Through curve fitting of the interfacial shear stress versus relative displacement scatter plots using exponential and inverse hyperbolic models, a bond-slip load transfer model incorporating initial frictional resistance (τ_c) was established. This model effectively characterizes the load transfer mechanism in filled-core composite solidified soil precast piles under loading conditions. The proposed methodology provides theoretical support for analyzing the bearing behavior and interfacial interaction mechanisms of this novel pile foundation system.